700R4 help

[1983_SB_4X4]

OK so I swapped out the stock 2-4 servo in my tranny for a Vette 2-4 servo, hoping that was my problem. But to no avail I still have no 4th or lock up. 2nd gear is now working ONLY when I manually move the selector through the gears?? If I put the selector in D and drive the tranny seems to go from 1st straight to 3rd & stays there. I'm turning about 2800 RPM @ 60-65 mph. Does anyone have any ideas??

 

[83K5guy]

Sounds like what mine does and I believe my 2-4 band is gone. Most likely a trans rebuild coming up. IMO

 

[HotRodPC]

OK so I swapped out the stock 2-4 servo in my tranny for a Vette 2-4 servo, hoping that was my problem. But to no avail I still have no 4th or lock up. 2nd gear is now working ONLY when I manually move the selector through the gears?? If I put the selector in D and drive the tranny seems to go from 1st straight to 3rd & stays there. I'm turning about 2800 RPM @ 60-65 mph. Does anyone have any ideas??

If I recall, this is also the symptoms of a stripped or broken sun shell. I'd have to check the flow charts to make sure. Usually when 2 and 4th go, but you have manually selected 2nd, that is the issue.

 

[HotRodPC]

Also, keep in mind, the Vette servo fixes nothing. It does firm up the shifts though, so be sure to keep that servo and use it on your rebuild. It's not so much a wearing part, so you can reuse it from build to build.

 

[1983_SB_4X4]

Also, keep in mind, the Vette servo fixes nothing. It does firm up the shifts though, so be sure to keep that servo and use it on your rebuild. It's not so much a wearing part, so you can reuse it from build to build.

Yes sir I didn't mean it to sound like I thought putting thee Vette servo in was a fixall. I went with Vette servo hoping it was bad O-rings on the stock servo, but to no avail. I'm really on a tight budget with this little truck at the moment. My wife lost her job back in November, and I was hoping to get this truck fixed to save me on some fuel. This $4 a gallon diesel is F'ing ridiculous. I've never rebuilt a transmission, but I have a feeling since parts are only $200+/- and a rebuilt trans is $700-$1000. I will be attempting a rebuild soon. I have a friend that said his son will loan me the tools to do the rebuild, so I may be forced to go that route. If anyone near or around San Antonio has a 700R4 from '88-'91 for 4x4 they want to sell reads this please let me know. I'm looking for one that doesn't need rebuilding, even if I have to pull it.

 

[1983_SB_4X4]

If I recall, this is also the symptoms of a stripped or broken sun shell. I'd have to check the flow charts to make sure. Usually when 2 and 4th go, but you have manually selected 2nd, that is the issue.

Had to come back & say thanks for your help HotRod. Sorry I forgot in the last post my minds been pretty cluttered trying to figure this dang trans out. The sun shell you mentioned (i'm by far nor trans expert) is it hard or expensive to replace??? How hard would it be to take a good 2 wheel drive 700r4 and pull the tail piece & swap output shafts so it would work on my 4x4????


Thanks!!!
Rob

 

[HotRodPC]

I checked my common failure chart. If it lost 2nd, 4th and Reverse, or reverse was not acting right or weird noise in Reverse, it would be the sun shell. If just 2nd and 4th are the problems, then its a wore out 2-4 band. Nonetheless, sounds like it needs to come out and be cracked open.
Take your year to buy out to 92. 88-92 were the better years, and hopefully a K case which is common for the 4x4 transmission.

 

[HotRodPC]

Had to come back & say thanks for your help HotRod. Sorry I forgot in the last post my minds been pretty cluttered trying to figure this dang trans out. The sun shell you mentioned (i'm by far nor trans expert) is it hard or expensive to replace??? How hard would it be to take a good 2 wheel drive 700r4 and pull the tail piece & swap output shafts so it would work on my 4x4????


Thanks!!!
Rob

The sunshell is the most common failure of the 700r4. I'd replace it with the stronger aftermarket part called The Beast. Usually about $40 and worth it. Unless its a race or your do heavy towing or heavy 4x4ing, no need for the newer even better smart shell, but that is an option too. Yes, you can convert a 2wd unit to a 4wd unit. You'd have to pull all the guts out of both, and swap the 4x4 output shaft into the 2WD trans, and leave the aluminum tailshaft housing off the trans. That's all there is to that.

 

[1983_SB_4X4]

The sunshell is the most common failure of the 700r4. I'd replace it with the stronger aftermarket part called The Beast. Usually about $40 and worth it. Unless its a race or your do heavy towing or heavy 4x4ing, no need for the newer even better smart shell, but that is an option too. Yes, you can convert a 2wd unit to a 4wd unit. You'd have to pull all the guts out of both, and swap the 4x4 output shaft into the 2WD trans, and leave the aluminum tailshaft housing off the trans. That's all there is to that.

Was just looking @ the TCI website & their "beast" is listed @ $80 something.... This will be just a little daily driver that will occasionally pull my boat & be used for some beach fishing trips hopefully. Nothing hardcore, just normal driving. My Reverse, 1st & 3rd work perfect. No slip, no hesitation, no grinding or howling. The trans works flawlessly in the gears it is actually grabbing. That is why when I pulled the original 2-4 servo & felt all the slop in it, I was really hoping this new servo & O-rings was going to fix it. Thanks once again & look forward to anything else you may have to offer for advice.

Oh yeah & I've already figured out that mine is an '88-'92 model with the auxiliary pump. I can't tell exactly what year because the serial number is gone, but I read somewhere that back in the day GM rebuilt 700r4's and would buff the serial # off & attach a tag (which I can't find lol) when they would rebuild the units.

 

[oneluckypops]

The sunshell is the most common failure of the 700r4. I'd replace it with the stronger aftermarket part called The Beast. Usually about $40 and worth it. Unless its a race or your do heavy towing or heavy 4x4ing, no need for the newer even better smart shell, but that is an option too. Yes, you can convert a 2wd unit to a 4wd unit. You'd have to pull all the guts out of both, and swap the 4x4 output shaft into the 2WD trans, and leave the aluminum tailshaft housing off the trans. That's all there is to that.

Its a piece of cake to swap the output shafts, Might Iremind you you will need a paper kit. Pump seal, pump Gasket, Valvebody gaskets, Filter and Pan gasket. Either way you go youll have help right here if you have any problems.

Make sure you check the endplay on the good Transmission before you start pulling it apart, if the specs are out you need to really look for worn parts that may not have failet YET.

 

[1983_SB_4X4]

Its a piece of cake to swap the output shafts, Might Iremind you you will need a paper kit. Pump seal, pump Gasket, Valvebody gaskets, Filter and Pan gasket. Either way you go youll have help right here if you have any problems.

Make sure you check the endplay on the good Transmission before you start pulling it apart, if the specs are out you need to really look for worn parts that may not have failet YET.

Thanks Luke for the advice.


Well you fellas have a good evening/mornin I got to try & get some sleep 5:15 is just around the corner. Damn truck has me so worked up I can't sleep.